The present invention relates generally to hydraulic gear pumps and more particularly to an improved shaft seal for a hydraulic gear pump.
In the manufacture of gear pumps, it is known that a high pressure seal is required to limit leakage of hydraulic fluid along the pump drive shaft. The amount of leakage along the drive shaft is primarily a function of pump output pressure. Thus, in small displacement pumps, the leakage along the drive shaft can seriously degrade the volumetric efficiency of the pump. Thus, a need has developed for a simple, reliable, and effective dynamic seal along the drive shaft of a gear pump to minimize the amount of leakage of hydraulic fluid along the shaft.